1. Field of the Invention
The present invention relates to an image processing apparatus, an image forming apparatus, and an image processing method.
2. Description of the Related Art
An image forming apparatus including a plurality of functions of a facsimile machine, a printer, a scanner, a copier, and the like, such as a multifunction printer or a digital multifunction product (MFP), has been in widespread use. The image forming apparatus creates image data on a document or the like by reading the document or the like with the scanner function, performs predetermined image processing on the created image data, and then outputs the processed image data to the printer function. Such an image forming apparatus has been disclosed in, for example, Japanese Patent Application Laid-open No. 2004-104442.
FIG. 16 is a block diagram of the image forming apparatus disclosed in Japanese Patent Application Laid-open No. 2004-104442. The image forming apparatus includes a scanner unit 901, an image processing unit 902, and a printer unit 903.
The image processing unit 902 includes a shading processing unit 902a, an interline-correction processing unit 902b, a scanner gamma processing unit 902c, a text/photo determining unit 902d, a color-correction processing unit 902e, a reduction/enlargement processing unit 902f, a shift processing unit 902g, a printer gamma processing unit 902h, and a tone processing unit 902i. Incidentally, the shading processing unit 902a, the interline-correction processing unit 902b, the scanner gamma processing unit 902c, and the text/photo determining unit 902d perform image processing on an input image that is an image read by the scanner unit 901. The color-correction processing unit 902e, the reduction/enlargement processing unit 902f, the shift processing unit 902g, the printer gamma processing unit 902h, and the tone processing unit 902i perform image processing on an output image that is an image to be printed by the printer unit 903.
However, users' needs with respect to the image forming apparatus vary greatly. Some users may demand a function other than those included in the image processing unit 902. For example, a variable range of a reduction/enlargement ratio of the reduction/enlargement processing unit 902f may vary among users.
However, if the conventional image forming apparatus is configured to meet the various needs, following problems occur.
As image data flows on a single data path from the shading processing unit 902a to the tone processing unit 902i, to add a new function, it is necessary to provide a new image processing unit for realizing the new function in this data path.
Furthermore, as the enlargement ratio increases, for example, an amount of data to be processed by the reduction/enlargement processing unit 902f disadvantageously increases. As the amount of data to be processed increases, the processing speed of the reduction/enlargement processing unit 902f decreases. If the processing speed of the reduction/enlargement processing unit 902f drops below the input speed of the scanner unit 901, the single data path is unable to absorb the speed difference between the reduction/enlargement processing unit 902f and the scanner unit 901. Consequently, a user can only change the reduction/enlargement ratio within such a range that the processing speed of the reduction/enlargement processing unit 902f is higher than the input speed of the scanner unit 901.
Namely, to meet various needs of users with a single image processing unit, an image processing unit having as many functions as possible needs to be employed, and thus a cost increases disadvantageously. By the way, as a method for coping with the various needs of users, for example, techniques disclosed in Japanese Patent Application Laid-open No. 2005-323406 and Japanese Patent Application Laid-open No. 2005-64639 are conceivable.
However, in the technique disclosed in Japanese Patent Application Laid-open No. 2005-323406, a plurality of units is just controlled so as to control a scanner data path, a printer data path, and the like efficiently. Moreover, in the technique disclosed in Japanese Patent Application Laid-open No. 2005-64639, a plurality of data paths is arranged in parallel so as to reduce a circuit size. Therefore, these techniques cannot meet the purpose of providing a multifunctional capability to a single image processing unit.